Today, we are announcing enhancements to Amazon EC2 Reserved Instances (RIs) that make them more flexible and easy to use, helping you get the most out of your RI discount.

In September 2016, we introduced “regional RIs”, which provide Availability Zone (AZ) flexibility and make it easier for customers to take advantage of their RI’s discounted rate. Customers could choose to forego the capacity reservation associated with their RI, run their instance in any AZ in the region, and have their RI discount automatically applied.

Effective March 1st, regional RIs now provide instance size flexibility, in addition to AZ flexibility. With instance size flexibility, your regional RI’s discounted rate will automatically apply to usage of any size in the instance family, and in any AZ. Let’s say you own an m4.2xlarge Linux/UNIX regional RI in US East (N.Virginia). The discounted rate of this RI can automatically apply to 2 m4.xlarge instances in us-east-1a or 4 m4.large instances in us-east-1b without you needing to do anything. Since the discounted rate is automatically applied to usage irrespective of size or AZ, you can save even more off your EC2 bill with no management overhead of trying to match RI discounts to running instances. With the instance size flexibility and AZ flexibility provided by regional RIs, customers no longer have to worry about being tied to a specific size or AZ, or worry about launching the right instance size in the right AZ to match their RIs. This helps you save time and money, and lets you focus on the performance and needs of your application.

Instance size flexibility is offered on Linux/UNIX regional RIs and is available at no additional cost. To learn more about how you can take advantage of RIs, please visit the Amazon EC2 Reserved Instances page.